Battery pack enclosure with controlled thermal runaway release system

Abstract

A battery pack thermal management system is provided that is comprised of at least one enclosure failure port integrated into at least one wall of a battery pack enclosure, where the enclosure failure port(s) remains closed during normal operation of the battery pack, and opens during a battery pack thermal runaway event, thereby providing a flow path for hot gas generated during the thermal runaway event to be exhausted out of the battery pack enclosure in a controlled fashion.

1. A battery pack thermal management system, comprising:
 a battery pack enclosure configured to hold a plurality of batteries, wherein said battery pack enclosure is comprised of a high temperature material; and 
 an enclosure failure port assembly integrated into a wall of said battery pack enclosure, wherein said wall of said battery pack enclosure has a first wall thickness, wherein said enclosure failure port assembly remains closed during normal operation of said battery pack, and wherein said enclosure failure port assembly opens during a battery pack thermal runaway event and provides a flow path for exhausting hot gas from within said battery pack enclosure, wherein said enclosure failure port assembly directs said flow path at an angle away from a normal of said wall of said battery pack enclosure, and wherein said enclosure failure port assembly further comprises: 
 a substantially circular region of said wall, said substantially circular region having a second wall thickness that is thinner than said first wall thickness; 
 a transition region interposed between said substantially circular region and a surrounding portion of said wall that surrounds said substantially circular region, wherein a first portion of said transition region encircling a first portion of said substantially circular region has a third wall thickness that is thicker than said second wall thickness and thinner than said first wall thickness, wherein a second portion of said transition region encircling a second portion of said substantially circular region has a fourth wall thickness that is thinner than said second wall thickness and thinner than said first wall thickness, wherein said second portion of said transition region fails before said first portion of said transition region during said battery pack thermal runaway event and allows hot gas from within said battery pack enclosure to exhaust through said substantially circular region at an angle away from said normal of said wall of said battery pack enclosure. 
 
     
     
       2. The battery pack thermal management system of  claim 1 , wherein said high temperature material is comprised of a metal with a melting temperature greater than 800° C. 
     
     
       3. The battery pack thermal management system of  claim 1 , wherein said high temperature material is comprised of a metal with a melting temperature greater than 1000° C. 
     
     
       4. The battery pack thermal management system of  claim 1 , wherein said high temperature material is comprised of at least an outer layer and an inner layer, wherein said inner layer is comprised of a ceramic. 
     
     
       5. The battery pack thermal management system of  claim 4 , wherein said ceramic inner layer prevents said outer layer from melting during said battery pack thermal runaway event. 
     
     
       6. The battery pack thermal management system of  claim 1 , wherein said high temperature material is comprised of at least an outer layer and an inner layer, wherein said inner layer is comprised of an intumescent material. 
     
     
       7. The battery pack thermal management system of  claim 6 , wherein said intumescent material inner layer prevents said outer layer from melting during said battery pack thermal runaway event. 
     
     
       8. The battery pack thermal management system of  claim 1 , wherein said battery pack enclosure further comprises:
 a first housing member configured to hold said plurality of batteries; 
 a second housing member configured to be coupled to said first housing member; and 
 means to secure said first housing member to said second housing member. 
 
     
     
       9. The battery pack thermal management system of  claim 8 , wherein said battery pack enclosure further comprises a sealing gasket configured to fit between a first sealing surface corresponding to said first housing member and a second sealing surface corresponding to said second housing member, said sealing gasket further configured to be interposed between said first and second sealing surfaces when said first housing member is secured to said second housing member. 
     
     
       10. The battery pack thermal management system of  claim 1 , wherein said enclosure failure port assembly opens when an internal battery pack temperature exceeds a preset temperature. 
     
     
       11. The battery pack thermal management system of  claim 1 , wherein said enclosure failure port assembly opens when an internal battery pack temperature exceeds a preset temperature and an internal battery pack pressure exceed a preset pressure. 
     
     
       12. The battery pack thermal management system of  claim 1 , further comprising a heat resistant channel, wherein an entrance of said heat resistant channel is proximate to said enclosure failure port assembly, and wherein during said battery pack thermal runaway event hot gas is exhausted out of said enclosure failure port assembly and into said entrance of said heat resistant channel. 
     
     
       13. The battery pack thermal management system of  claim 12 , wherein said battery pack enclosure is mounted to a vehicle, wherein said hot gas exhausted through said enclosure failure port during said thermal runaway event passes through said heat resistant channel, and wherein an exit port of said heat resistant channel directs said hot gas away from a vehicle passenger compartment. 
     
     
       14. The battery pack thermal management system of  claim 12 , wherein said heat resistant channel utilizes an open channel design. 
     
     
       15. The battery pack thermal management system of  claim 12 , wherein said heat resistant channel utilizes a closed channel design. 
     
     
       16. The battery pack thermal management system of  claim 1 , wherein said battery pack enclosure is mounted to a vehicle, wherein said battery pack thermal management system further comprises at least one layer of a thermal insulator positioned between said battery pack enclosure and a vehicle passenger compartment. 
     
     
       17. The battery pack thermal management system of  claim 1 , wherein said battery pack enclosure is mounted to a vehicle, wherein said battery pack thermal management system further comprises at least one layer of a fire retardant material positioned between said battery pack enclosure and a vehicle passenger compartment. 
     
     
       18. The battery pack thermal management system of  claim 17 , wherein said fire retardant material is comprised of an intumescent material.